In known flushing devices for a vacuum toilet with, for example, a urinal, after use of the urinal, first a flushing liquid is supplied to the urinal, and subsequently a suction removal valve is opened in order to transport urine, flushing liquid and other impurities into the region of a waste water tank. Often a closing valve is provided in the waste water line in order to control the suction removal process or to acoustically seal the waste water system off from the vacuum system during the suction process. Frequently, clogging in the drain system occurs, for example due to impurities or dirt, so that usually an overflow device is provided in order to prevent damming up in the urinal, wherein this overflow at some location needs to be led back into the drain system in order to reliably drain off overflowing liquid. In this arrangement drainage devices, such as an overflow or a main drainage, must make it possible for a liquid to reliably flow off, and it must ensure sealing off of odour relative to the waste water or the drain system.
In stationary sanitary applications, the requirements of liquids outflow and sealing off of odour are met with the use of odour seals. However, the embodiments of these odour seals from stationary sanitary applications are designed only for a pure outflow function without vacuum suction removal, and consequently they cannot be used in vacuum systems involving high volume flows. In the hitherto commercially available odour seals in a vacuum system the noise emissions that arise during the flushing process are excessive, and consequently in this respect there is a need for improvement.
From DE 10 2007 004 832 A1 a drainage device with an odour seal for a vacuum toilet drain system is known.